Cargo barrier nets which restrain cargo carried in an aircraft are known in the art. Such are particularly prevalent in freighter aircraft, which have been converted from passenger aircraft, to prevent the intrusion of cargo into the crew area in the event of a severe forward load on the aircraft. Most of these known nets are fabricated of high-elongation materials such as nylon or polyester strap webbing. However, such materials are quite heavy, having a low strength-to-weight ratio. In order to add strength to these nets, additional strands of webbing to resist stretching are required, but such only compounds the weight problems already existent in these nets. As such, most manufacturers allow maximum stretching of these nets which has the disadvantage of not being able to utilize all available space for cargo, the space rather being used to accommodate the stretching of the net.
A net woven of thread sold under the trademark KEVLAR.RTM. would be a solution to the aforementioned problems in that this material is lighter weight, having a much higher strength-to-weight ratio, and exhibits a very low stretch at failure. However, to date, no one has been able to develop a cargo barrier net of KEVLAR.RTM. in that fabricating such a net with sufficient accuracy to prevent unbalanced loads on individual web members is extremely difficult. Thus, the need exists for a cargo barrier net fabricated of a high strength-to-weight ratio material such as KEVLAR.RTM..
The webbing or straps which form cargo barrier nets, fabricated of any known material, usually intersect at approximately right angles and are conventionally box stitched or otherwise attached at their intersection. However, for high strength-to-weight materials, such as KEVLAR.RTM., such attachment could well represent areas for failure, and known stitching would not accommodate other than right angle intersections.
In addition, the hardware utilized to attach the periphery of prior art cargo barrier nets to the aircraft is not without its problems. Such hardware is quite heavy and expensive and has, in the past, been permanently attached to the fabric. As such, when the fabric wore out or otherwise failed and had to be replaced, either the hardware had to be replaced as well or the hardware had to be cut off the fabric, sent back to the manufacturer, and reattached to the new fabric. Moreover, the fabrication of a net with the hardware attached thereto is much more difficult in that the hardware adds significant weight to the already heavy fabric, rendering the maneuverability of the net during the fabrication thereof and subsequent unwieldy shipment thereof expensive.
Finally, for loading and/or unloading cargo on an aircraft, at least the top, bottom and one side of the peripheral net attachments must be disconnected from the aircraft and then reattached when the cargo is in place. When utilizing a material for the net having a high strength-to-weight ratio, because there is minimal elongation at load, the net must be fabricated to be preformed in the shape of its loaded condition so that any force thereon is in the longitudinal direction of the aircraft. Thus, the top net attachments are not readily within reach and therefore, when using these materials, an alternative and simpler manner of moving the net out of the way of the cargo being loaded and/or unloaded is required.
In short, the need exists for a lightweight, high strength aircraft cargo barrier net. But in order to accomplish such, specialized attachment of the intersecting webbing as well as unique hardware devices is desirable, if not required.